Valve seat grinder



W. K. BECKWITH ApvE SEAT GRINDER March 16, '51943.

Filed March 17, 1941 Efg;

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ATTORNEY'.

ZU 2M ``/NVNTOF z v I i Patented Mar. 16, 1943 VALVE SEAT GRINDER Wendell K. Beckwith, Milwaukee, Wis., assignor to Milwaukee Electric Tool Corporation, Milwaukee, Wis., a corporation of Wisconsin Application March 17, 1941, Serial No. 383,655

8 Claims.

My present invention relates generally to improvements in the art of dressing annular surfaces, and relates more specifically to improvements in the construction and operation of tools for grinding tapered annular surfaces such as valve seats or the like.

An object of the invention is to provide an improved valve seat grinder which is simple in construction and efiicient in operation.

The valves and valve seats .of vehicle propelling motors such as the ordinary internal combustion automcbile engine, frequently require refinishing in order to insure tight closing or proper seating, and it has heretofore been common practice to utilize a relatively complicated 'but rather eficient motor driven grinding tool for this purpose. In this prior valve seat grinding tool, a casing is mounted for rotation about a 'pilot pin which is inserted in the valve stem guide hole located concentrically of the tapered seat which is to be reground, and a rotary grinding wheel supporting shaft is journalled in the .casing eccentrical'ly of but parallel to the pilot pin axis,-so that by rotating the casing the independently rotating grinding wheel will be g-yrated labout ythe vpilot axis and will travel along the tapered seat in line contact therewith. Because of the fact that the grinding wheel carrier shaft of this :prior tool, travels in an annular path and is always maintained parallel vto the pilot pin axis, this lprior ztool ;is-necessarily rather bulky and complicated in structure, .thus making it cumberscme to handle and rather Vexpensive Vto maintain in Operating conditicn.

lIt 'is `therefore a more specific object of my present inventicn to provide a .new Aand useful valve seat grinder wherein the rotating grinding wheel may likewise be .gyrated ,in line contact with .a 'tapered valve seat, but whichis far-more compact and simpler'than the prior device.

Another specific object of this invention is to .provide an improved valve .seat dressing tool which is more durable `Vin ccnstructiomin which the dressing Wheels vhave prolonged life, and which is efiectvely operablein cramped quarters.

Stillanother specific objectcftmyzinvention is to provide an improved device wherein a grindvwheel is rapidly rotatableabout oneaxis and automatically .gyratable at reduced speed about another eccentric axis so as tooslowly advance 'the wheel about the central axis of the Work.

A iurther specific object uof the linvention is .to provide an improved Valveoseat hrefinishing assemblage which is always readyfor use, and which can be manufactured and sold at moderate cost, and which is adapted to be applied as an attachment or accessory to an ordinary driving motor. These and other specific objects of the invention will be apparent from the following detailed description.

A clear conception of an embodiment of the invention, and of the modeof constructing and of utilizing one of the improved tapered valve seat grinders, may be had by referring to the drawing accompanying and forming a part of this specification wherein like reference characters designate the same or similar parts in the various views.

Fig. 1 is a central Vertical section through one of the improved valve seat grinders showing -the same coacting with a tapered valve seat and applied to a driving spindle; and

Fig. 2 is a transverse section through the assemblage of Fig. 1, taken along the line 2-2.

While the invention has been shown and de-A scribed herein, as having .been specifically embodied in a portable .tool or attachmentespecially adapted for dressing the tapered valve seats of standard automobile engines, it is not my desire or intent to .therreby urmecessarilylimit .the scope or-utility of the improvement.

;Referring to the drawing, the improved valve seat grinder shown therein by way .of illustration comprises ingeneral, a, main housing or casing consisting of .an` inner section 5 snugly co'nfined within an -outer section tli; :an upper closure and driving end head Ti attached vby screw threads to the inner casing section .5 and ,having a central `polygonal socket .8 .adapted fcrdetachable reception of the polygonalvdriving .head 9 of a motor operated 'spindle Jil; a lower head -i i .formed integral withtthe -outer casing section and-having va threaded sleeve [2 depending centrallyitherefrom; antapered grinding wheel-E3 having a screw vthreaded central core Hi adpted fordetachable attachrnvent to the ythreaded sleeve 1,2; ta-tubular memberor bearing sleeve I havingan internal .boliei and alongitudinal key-way H; and being disposedwithin the inner casingsection 5; a, concentric ball bearng interposedr between the upper ends of the casing section vii and sleeve I 5,' and havingan annular seriesof bearinglballs IB co- `acting .Withouter and inner ballraces |9,,20 reand with the valve stem guiding hole in a standard engine block 21, and having thereon a key 20 adapted for sliding coaction with the key-way I'.

The outer and inner cylindrical casing sections 5, 6 may be fitted snugly within each other so as to provide a friction drive for the wheel |3, but these sections may also be positively drivingly interconnected in any desirable manner as by a set screw 29 cooperable with a slot 30 in the inner casing section 5. The socket 8 and driving head 9 are formed hexagonal or of any other polygonal shape, and the head 9 preferably has a loose fit Within the socket 8 so as to permit wobbling motion between the spindle l and the casing Sections 5, 6. The spindle |0 is ordinarily adapted to be driven by means of a relatively high speed rotary motor, such as an electric motor, and ordinarily has its axis disposed in approximate alinement with the pilot pin 25. The interior of the head 1 may be provided with a closure plate 31, and the lower end of this head 'l is adapted to clampingly engage the upper outer ball race l9. The clamping action exerted upon this upper race 19 may be transmitted through a collar 32 snugly confined within the inner casing section 5, to the lower outer roller race 24, to thereby clamp this race 24 against the lower integral end wall 33 of the casing section 5. The upper inner race 20 may be clamped to the upper end of the sleeve by means of a ring nut 34, so that this race will normally be held stationary. As previously indicated, the upper annular ball bearing is disposed concentric with the axis of the pilot pin 26, while the outer race 24 of the lower roller bearing'is eccentric with respect to this axis; and while the grinding wheel |3 which is suspended from the lower extremity of the main casing is rotatable about the common axis of the two outer races 10, 24, this wheel l3 may be simultaneously revolved or gyrated about the pilot pin axis so as to travel in line contact with and around the inclined valve seat 35. In order to permit this to be done, the bearing surfaces of the ball and roller bearings are preferably specially formed. The bearing groove 36 in the inner upper ball race may be formed to provide for line contact with the bearing balls |8, but the bearing groove 31 in the outer upper race |9 is preferably formed with a larger radius of curvature, so as to permit the ring race |9 to be tilted slightly relative to the balls |8. While the annular series of bearing balls |8 iscontinuous, there are only four equally spaced rollers 2|, 22, 23, and these are mounted on parallel pins 38 carried by annular spacer plates 39. The roller 2| has smallest diameter, and the diametrically opposite rollers 22 have equal diameter, while the roller 23 has largest diameter; and all of these bearing rollers are crowned and have point contact with the lower bearng surface 25 of the central sleeve |5. The bearing groove of the lower race 24 is curved to provide approximately line contact at the outer portions of the rollers 2l, 22, 23, while permitting gyration of the race 24 relative to the sleeve I and pin 26.

During normal use of the improved valve seat grinder, the valve will naturally be removed from the engine block 21 preparatory to grinding the tapered valve seat 35, whereupon the pilot pin 26 may be positioned within the valve stem guiding hole centrally of the annular seat. The improved gyrator assembly may then be applied to the pin 23 with the key-way l' coacting with the key 20, whereupon the tapered portion of the emery or grinding wheel I 3 should have line con- 'tact with one portion of the tapered seat 35 as shown in Fig. 1. The wheel |3 should be properly dressed in the usual well known manner to provide for such line contact, and the casing sections 5, 6 may be adjusted longitudinally of each other with the aid of the slot 30 and set screw 29 to produce the desired radius of gyration for the wheel |3 about the pilot pin axis. The driving spindle |0 may then be applied about mdway into the tool socket 8, and thereafter rotated to cause the wheel |3 to revolve and to simultaneously gyrate about the central axis of the seat. Since most work is performed in such manner that gravity will constantly urge the assemblage toward the valve seat 35, it is not necessary to apply manual downward pressure to the tool. The grinding wheel |3 will then be automatically gyrated about the axis of the pin 26 at a reduced speed, but still sufiiciently rapid to maintain the wheel in Suspension over low spots while contacting and reducing high spots, prior to continuous ifinal dressing of the entire seat 35. After the reseating operation has been completed, the tool 'assemblage may be quickly removed and applied to another valve seat.

From the foregoing detailed description, it will be apparent that the present invention provides 'a simple. compact and highly efiicient valve seat grinding assemblage especially adapted to dress or grind the tapered valve seats of relatively standard internal combustion engines or automobile motors. The appliance may obviously be readily appliedvto an engine block 21 or any other type of work and operated by a novice, to produce accurate results, and is so compact that it can be effectively operated in relatively cramped quarters. The interior of the main casing and the surfaces of the sleeve I may be readily formed since there are no eccentrically machined surfaces on any of the parts, and it is to be noted that the eccentricity is produced solely by the diiference in diameter of the rollers 2 l, 22, 23. In actual practice, there should be slight interval in the eccentric bearing assemblage, so that only one of the four rollers will carry the gyrating load, depending upon the disposition of the forces produced by unbalanced centrifugal force and grinding pressures.

The important feature of the present invention is the eccentric roller bearing which may be utilized to advantage in any assemblage wherein it is desired to simultaneously rotate a member at relatively high speed, and to gyrate the member at a slower speed. By supporting the outer race 24 of the roller type anti-friction bearing, on rollers 2|, 22, 23 of different diameters, these rollers function to reduce the speed of gyration below that of the speed of rotation of the member or wheel l3, and this fact produces a wiping or cleaning action at the zone of grinding and also results in uniform distribution of the wear on the grinding wheel |3. While the intersection of the axis of the wheel E3 and pin 26 is the result of the use of an ordinary upper concentric ball bearing in the present assemblage, such intersectiori is not essential, and does not contribute to the advantageous action of the lower eccentric bearing. The interior of the rotating housing or casing may be abundantly supplied with lubricant such as grease so as to maintain the tool in constant readiness for use, and the improved device can obviously be manufactured and sold at moderate cost due to its extreme simpliicty. The improved structure is however durable in construction and is adapted to speedily perform its duty in a highly efiicient manner.

It should be understood that it is not desired to limit this invention to the exact details of construction, or to the precise mode of use, herein shown and described, for various modifications Within the scope of the appended claims, may occur to persons skilled in the art.

I claim:

1. In combination, a circular support having a central axis, an annular member surrounding said support and being rotatable about an axis dsposed eccentrically relative to said support axis, means for rotating said member about its own axis, and a roller bearing having rollers of different diameters interposed between said support and said member for automatically gyrating said member about said support axis during rotation of the member.

2. In combination, a circular support having a central axis, an annular member surrounding said support and being rotatable about an axis dsposed eccentrically relative to said support axis, means for rotating said member about its own axis, and an anti-friction bearing having rotary elements of different diameters interposed between said support and said member for gyrating said member about said support axis during rotation of the member.

3. In combination, a circular support having a central axis, an annular member surrounding said support and being rotatable about an axis intersecting said support axis, means for rotating said member about its own axis, and an anti-friction bearing having rotary elements of different diameters interposed between said support and said member for gyrating said member about said support axis during rotation of the member.

4. In combination, a pilot pin, an annular support slidably engaging said pin, a casing surrounding said support and being rotatable about an axis dsposed eccentrically relative to the central axis of said support, means for positively rotating said casing about its own axis, and a bearing having an annular series of rotary antifriction elements of diiferent dimeters interposed between said support and said casing for automatically gyrating said casing about said support axis during rotation of the casing.

5. In combination, a pilot pin, an annular support slidably engaging said pin, a casing surrounding said support and being rotatable about an axis intersecting the central axis of said support, means for positively rotating said casing about its own axis, and a bearing having an annular series of rotary anti-friction elements of different diameters interposed between said support and said casing for automatically gyrating said casing about said support axis during rotation of the casing.

6. In combination, a pilot. pin adapted for disposition centrally of an annular valve seat, a sleeve splined upon said pin, a casing surrounding said sleeve and being rotatable about an axis intersecting the central axis of said sleeve remote from the valve seat, means for positively rotating said casing about its own axis, an annular grinding wheel suspended from said casing adjacent to the valve seat, and a bearing having an annular series of rotary anti-friction elements of different diameters interposed between said sleeve and said casing for gyrating said wheel about said sleeve axis during rotation thereof about said casing axis.

7. In combination, a pilot pin having one end adapted for fixed disposition centrally of an annular tapered Valve seat, an annular casing surrounding said pin and being rotatable about an axis intersecting the' central axis of said pin remote from the valve seat and beyond the op- 'posite free end of the pin, an annular grinding wheel suspended from said casing between said pin ends and adjacent to the valve seat, and an eccentric bearing interposed between said casing and said pin adjacent to said wheel for gyrating said wheel about said pin axis during rotation of the wheel about said casing axis.

8. In combination, a pilot pin having one end adapted for fixed disposition centrally of an annular tapered valve seat, a sleeve splined on said pin, an annular casing surrounding said sleeve and being rotatable about an axis intersecting the central axis of said sleeve remote from the valve seat and beyond the opposite free end of said pin, an annular grinding wheel suspended from said casing between said pin ends and adjacent to the valve seat, and an eccentric bearing interposed between said casing and said vsleeve adjacent to said wheel for gyrating said Wheel about said sleeve axis during rotation of the wheel about said casing axis.

WENDELL K. BECKWITH. 

